BOSTON -- Celtics center Shaquille O'Neal missed Wednesday's 118-116 win against the Knicks in New York due to a sore right calf.

O'Neal

It was not clear if he would be available for Thursday's game in Atlanta either.

O'Neal's absence kept rookie Semih Erden in the starting lineup. Celtics coach Doc Rivers hinted Tuesday that the Celtics would lean heavily on the Kevin Garnett/Glen Davis combo anyhow, but Boston's preference is to be able to bring Davis off the bench. Nonetheless, Erden had the tall task of helping defend the offensively dangerous Amare Stoudemire at the start of the game.

"Whoever we start at center will guard [Stoudemire]," Rivers said Tuesday. "We're a help defense team anyway. So whoever starts at center will post him. I don't think we'll do much different. Obviously, there will be times when Baby and Kevin are on the floor together and that will be an effective lineup for us as well."

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O'Neal has missed the past two games with the calf injury. He said Tuesday that he felt better as he replenished his "calf juices," but he did not participate in Tuesday's practice, which Rivers had previously said would indicate whether O'Neal was able to play in Wednesday's game.

Also, O'Neal will conduct the Boston Pops orchestra in Leroy Anderson's "Sleigh Ride" during a concert Monday night at Symphony Hall, in a program otherwise conducted by Keith Lockhart focusing on Christmas and holiday-season music.

Chris Forsberg is the Celtics reporter for ESPNBoston.com. Follow him on Twitter. Information from The Associated Press was used in this report.